If you read enough, there's a similarity  between things that make it easy, because this thing is like this other thing.  If you have a broad framework, then you have a place to put everything.  If you want to learn science, reading  the history of scientists and the story of scientists about when they were confused and what tools or insights allowed them to make the progress they make. 
So you have the timeline, or you have the map, or you have the branches of science  and what's known and what's not known.  So, incremental knowledge is so much easier  to maintain in a rich way than, you know, the first time somebody is telling you about Rome.  Why am I reading about Rome, I'm reading about Queen Victoria. 
At first it is very daunting.  But then as you get the kind of scope, then all these pieces fit in.  So it's fun to say, okay, this is where this belongs and  does this contradict something I knew before? 
And I better look that up, I better figure it out.  You know, it really bothers you when  you read things, and there's some inconsistency.  If you take a chessboard and randomly place the pieces and ask a chess person to memorize it, they can't do it, because everything about chess positions is about the logic of how things developed. 
So if you show them a position that's illogical  or incorrect, you would never get to, their encoding system isn't set up to absorb that.